1. Field of the Invention
This invention relates to beam constructions and the method of manufacture of beams, particularly those used for industrial storage racks, such as pallet racks, and similar purposes.
2. Description of the Prior Art
An adjustable storage rack and beam constructions therefor are shown in Kimpton U.S. Pat. No. 3,194,408 issued July 13, 1965. In this patent the beam has spaced parallel flanges, a central web portion perpendicular to and between the flanges, and inclined web portions connecting the central web portion with the flanges.
The illustrated embodiment of the present invention discloses this basic construction in a double form, that is, with two such beams in facing and interfitting relation. It is known to form beams, for example, of channel-shaped construction with identical dimensions, and overlap the flanges of such beams to form a closed box. The channel members are then secured together. A disadvantage of such constructions is that it is often difficult to obtain a good fit, with both sets of flanges in good contact. Lack of a proper fit could detract from the load capacity of the beam.
Another disadvantage of conventional closed beam construction used in industrial storage environments if the vulnerability of the beam edges to denting and other abuse from impact, for example, caused by a forklift truck.
It is an object of the present invention to overcome some of the disadvantages of the previous beam constructions used for industrial storage purposes, and to provide a novel and improved beam construction, and method of manufacture, which reduces the weight requirements for a given load capacity.
It is another object to provide an improved beam construction and method of manufacture which is highly resistant to horizontal impact forces such as might be incurred by moving vehicles in a storage area.
It is another object to provide an improved method of constructing beams which insures the formation of a closed type of beam with a relatively good fit between the beam sections, thereby enhancing the load capacity.
It is also an object to provide an improved beam construction of this nature which offers a convenient surface on the aisle side of the beam for affixing labels or other markings which will not be easily brushed off.
Briefly, the beam construction of this invention comprises first and second beam sections, each section comprising a pair of spaced parallel flanges, a central web portion between and at right angles to said flanges and spaced therefrom, and first and second inclined web portions connecting the edges of the central web portion to the edges of the flanges on the same side thereof, the outer surfaces of the flanges of said second beam section fitting snugly within the inner surfaces of the flanges on the first beam section, whereby the sections together form a closed beam, and means securing said beam sections together.
The method of the present invention comprises a method of constructing a closed beam comprising the steps of placing two elongated flat metal plates having the same width in stacked relation, simultaneously bending said plates so as to form two nested beam sections with each section having a pair of spaced parallel flanges, a central web portion between and at right angles to said flanges and spaced therefrom, and first and second inclined web portions connecting the edges of said central web portion to edges of said flanges on the same sides thereof, removing the inner beam section from the outer section, reversing the inner section with respect to the outer section, slipping the flanges of the inner section between the flanges of the outer section until they overlap to a substantial extent, and securing said sections together.